Many racking systems for mounting or supporting photo-voltaic (PV) solar panels or modules on roofs or on the ground are commercially available. PV systems are expected to have a 25-year lifespan, and array wire management solutions should match this expectancy. However, designers and installers face persistent challenges to managing free-air conductors within the PV array.
Implementing a safe, reliable and Code-compliant wire management system for exposed PV conductors is not an easy task. PV module leads can be too long or sometimes too short, requiring site-specific solutions for supporting and interconnecting the cables. Equipment grounding, PV source-circuit and inverter-output conductors from micro-inverters and alternate current (AC) modules must also be managed to ensure protection from potential damage. Within the PV array, these various conductors are often secured to module frames, support rails and other racking system components. While securing array wiring seems as though it should be a straightforward exercise, the reality is that integrators continue to face numerous challenges.
UV-rated plastic wire ties provide a flexible, convenient and low-cost solution for bundling and fastening array conductors, but they are not a permanent answer and require regular inspection and replacement. Stainless steel cable clips work well for attaching conductors to the module frame, but this solution is often limited to supporting only one or two conductors at a time, and not all modules have frames. Structural channels or integrated cable management solutions within the module support rails assist with protecting and routing conductors, yet precautions must be taken where conductors enter and exit the channels to protect them from sharp edges that may compromise their insulation. In addition, module rails tend to run either east-west or north-south, but not both, so the rails may not provide support where conductors run perpendicular to the particular rail alignment.
Unfortunately, the PV industry lacks consistent, standardized wire management solutions for free-air conductors within the array. Coupled with the harsh environmental conditions that PV array conductors are exposed to—UV radiation, high winds and extreme ambient temperatures, and ice, snow and other debris—wire management continues to be the Achilles heel of the majority of PV installations.
The majority of PV systems have integrated leads, or wires, used for making electrical connections between modules. The module leads and the associated homerun conductors are often installed in free air within the PV array—meaning they are not in conduit. These exposed circuits contain potentially lethal voltages and currents that could electrocute someone, or cause a fire, in a faulted condition.
Although many racking systems are available, it has been found that the systems do not provide labor predictability, or provide predictable results based on structural needs or on-site requirements.
As a result, there remains a need for wire management solutions that can endure the extreme environments in which PV arrays are installed while ensuring the systems are safe and reliable.